"Bryan LaHair is our first baseman," Epstein said. "I don't believe in the concept of 4A players. The guy can hit."

The "4A hitter" is as old as the minor leagues themselves; it's the idea that some players are just too good for Triple-A but not good enough for the majors. For every guy who figures things out late like Nelson Cruz, or even far less than star-level players like Jorge Cantu, there are plenty of Triple-A sluggers like Kila Ka'aihue, Brad Eldred, or going back more to Calvin Pickering and Sam Horn, who put up crazy numbers but never had big league careers.

Are they 4A hitters? Does such a thing even exist? Are 4A hitters simply players who never got the right shot or got cold at the wrong time and never received the opportunity to un-bury themselves? Or are there some players who simply can't handle the job? I talked to several people in the industry to get their answers.

While not everyone even agrees on the existence of such players, there were three main ways a player can earn that label:

He has to really hit

One National League executive doesn't really believe in the concept of the 4A hitter. "I don't think it's that 4A-type guys can't hit major league pitching so much as it's 4A-type guys have no value besides their bat," he explains. "If you are a bad first baseman, or left fielder, or designated hitter, just being an average big league hitter doesn't really cut it, so you better hit the moment you get an opportunity or the industry moves on to someone else."

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